This application claims the priority of German patent application 10 2008 011 240.2-035, filed Feb. 26, 2008, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a system for connecting a transmit/receive (T/R) module to a testing device, particularly in the case of active antennas in the high-frequency range.
According to the state of the art, T/R modules (which in this case constitute a test item) can be contacted and evaluated by installation in special testing mounts. The high-frequency connection to the tester environment is established by coaxial connectors, and the high-frequency connection to the test item is established by adaptors with bonded wires and/or small bands. The supply of direct current and connection to the control signals are effected in a similar manner. After the test has taken place, the bonded connections are removed again, but remnants of the connection and visible traces remain on the connecting pads of the test items.
Alternatively, such mechanically high-expenditure (and also not traceless or residue-free) contact with test items may be provided by needle adapters for the low-frequency control or direct-current supply.
For this purpose, the high-frequency signals are fed via special coaxial test probes (high-frequency probes). In this type of contact, both the needles and the test probes leave traces (scratches) on the connecting pad during the contacting, and such traces (scratches) could impair further processing of the modules (installation into a system by bonding connection). In addition, for reasons of space and high-frequency-related demands, the connecting pads are kept very small. Therefore, in order to ensure secure contact of the modules for the measurement, both the test item and the test probes must be optically aligned manually with one another using a microscope, independently of another. Only this fairly high-expenditure approach ensures that the individual mechanical tolerances of the test items do not disturb the electrical characteristics of the modules. It should further be noted that the quality of the contact has a direct effect on the quality of the measuring results, and qualitatively high-value contacts are achieved only by experienced operating personnel.
In this type of contacting, the respective testing probes must be aligned individually, typically by using optical methods under a microscope, which is very time-consuming. Furthermore, the quality of the contacting is highly dependent on the skill of the operating personnel.
One object of the present invention, therefore, is to provide a system for contacting T/R modules which eliminates the disadvantages of the above-described contacting methods.
Another object of the invention is to achieve a high quality contact that is easy to handle and can be reproduced.
These and other objects and advantages are achieved by the system according to the invention, in which the optical alignment of the test item is replaced by mechanically guiding and centering a frame-shaped contacting unit on the frame of the T/R module to be tested, so that all connections can be made in a single operation. A line substrate (constructed as a shielded triplate line) arranged on the contacting unit establishes the connection to the connection ports of the testing device. The contacting unit has contact elements (for example, spring contact pins) connecting the line substrate with the corresponding contact pads of the T/R module.
The requirement for individual alignment of the testing probes with the test item in order to assure secure and reliable connection to the T/R modules, is eliminated by the contacting system according to the invention, as is the need for viewing through a microscope.
All required contacts (i.e., in addition to the high-frequency, low-frequency or DC signals) can be reliably and simultaneously closed in one operation.
With the system according to invention, the quality of the contact is largely independent of the skills of the operating personnel, thereby ensuring that the characteristics of the test items are accurately represented.
Another advantage of the system according to the invention is that calibration of the test setup, for which the same contacting principle can be used, can be carried out very simply. The calibrating elements for this purpose have the same construction as the line substrate, and have co-planar lines of different lengths which are mounted on a metal carrier. The metal carrier has an outer contour that approximates the test item, and can be inserted into the testing mount and contacted equally as easily as the T/R modules. No additional expenditures are required for adjusting and aligning for this purpose. Even the inserting sequence can be predefined by the control program for the operator.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.